druid是阿里巴巴开源的数据库连接池，提供了优秀的对数据库操作的监控功能，本文要讲解一下springboot项目怎么集成druid。

本文在基于jpa的项目下开发，首先在pom文件中额外加入druid依赖，pom文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dalaoyang</groupId>
    <artifactId>springboot_druid</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springboot_druid</name>
    <description>springboot_druid</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.12.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.28</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

application.properties上半段和整合jpa一点没变，下面加入了一些druid的配置，如果对druid的配置有什么不理解的，可以去网上查一下。（这篇文章我觉得写的很好，传送门）

#端口号
server.port=8888

##validate  加载hibernate时，验证创建数据库表结构
##create   每次加载hibernate，重新创建数据库表结构，这就是导致数据库表数据丢失的原因。
##create-drop        加载hibernate时创建，退出是删除表结构
##update                 加载hibernate自动更新数据库结构
##validate 启动时验证表的结构，不会创建表
##none  启动时不做任何操作
spring.jpa.hibernate.ddl-auto=create

##控制台打印sql
spring.jpa.show-sql=true

##数据库配置
##数据库地址
spring.datasource.url=jdbc:mysql://localhost:3306/test?characterEncoding=utf8&useSSL=false
##数据库用户名
spring.datasource.username=root
##数据库密码
spring.datasource.password=root
##数据库驱动
spring.datasource.driver-class-name=com.mysql.jdbc.Driver


#这里是不同的
#使用druid的话 需要多配置一个属性spring.datasource.type
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource  


# 连接池的配置信息
# 初始化大小，最小，最大
spring.datasource.initialSize=5  
spring.datasource.minIdle=5  
spring.datasource.maxActive=20  
# 配置获取连接等待超时的时间
spring.datasource.maxWait=60000  
# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
spring.datasource.timeBetweenEvictionRunsMillis=60000  
# 配置一个连接在池中最小生存的时间，单位是毫秒
spring.datasource.minEvictableIdleTimeMillis=300000  
spring.datasource.validationQuery=SELECT 1 FROM DUAL  
spring.datasource.testWhileIdle=true  
spring.datasource.testOnBorrow=false  
spring.datasource.testOnReturn=false  
# 打开PSCache，并且指定每个连接上PSCache的大小
spring.datasource.poolPreparedStatements=true  
spring.datasource.maxPoolPreparedStatementPerConnectionSize=20  
# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
spring.datasource.filters=stat,wall,log4j
# 通过connectProperties属性来打开mergeSql功能；慢SQL记录

然后在项目中加入DruidConfig，简单讲解一下，这个配置文件主要是加载application.properties的配置，代码如下：

package com.dalaoyang.config;

import java.sql.SQLException;

import javax.sql.DataSource;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import com.alibaba.druid.pool.DruidDataSource;
/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.config
 * @email yangyang@dalaoyang.cn
 * @date 2018/4/12
 */
@Configuration
public class DruidConfig {
    private Logger logger = Logger.getLogger(this.getClass());

    @Value("${spring.datasource.url}")
    private String dbUrl;

    @Value("${spring.datasource.username}")
    private String username;

    @Value("${spring.datasource.password}")
    private String password;

    @Value("${spring.datasource.driver-class-name}")
    private String driverClassName;

    @Value("${spring.datasource.initialSize}")
    private int initialSize;

    @Value("${spring.datasource.minIdle}")
    private int minIdle;

    @Value("${spring.datasource.maxActive}")
    private int maxActive;

    @Value("${spring.datasource.maxWait}")
    private int maxWait;

    @Value("${spring.datasource.timeBetweenEvictionRunsMillis}")
    private int timeBetweenEvictionRunsMillis;

    @Value("${spring.datasource.minEvictableIdleTimeMillis}")
    private int minEvictableIdleTimeMillis;

    @Value("${spring.datasource.validationQuery}")
    private String validationQuery;

    @Value("${spring.datasource.testWhileIdle}")
    private boolean testWhileIdle;

    @Value("${spring.datasource.testOnBorrow}")
    private boolean testOnBorrow;

    @Value("${spring.datasource.testOnReturn}")
    private boolean testOnReturn;

    @Value("${spring.datasource.poolPreparedStatements}")
    private boolean poolPreparedStatements;

    @Value("${spring.datasource.maxPoolPreparedStatementPerConnectionSize}")
    private int maxPoolPreparedStatementPerConnectionSize;

    @Value("${spring.datasource.filters}")
    private String filters;

    @Value("{spring.datasource.connectionProperties}")
    private String connectionProperties;

    @Bean
    @Primary  //主数据源
    public DataSource dataSource(){
        DruidDataSource datasource = new DruidDataSource();

        datasource.setUrl(this.dbUrl);
        datasource.setUsername(username);
        datasource.setPassword(password);
        datasource.setDriverClassName(driverClassName);

        //configuration
        datasource.setInitialSize(initialSize);
        datasource.setMinIdle(minIdle);
        datasource.setMaxActive(maxActive);
        datasource.setMaxWait(maxWait);
        datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setValidationQuery(validationQuery);
        datasource.setTestWhileIdle(testWhileIdle);
        datasource.setTestOnBorrow(testOnBorrow);
        datasource.setTestOnReturn(testOnReturn);
        datasource.setPoolPreparedStatements(poolPreparedStatements);
        datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
        try {
            datasource.setFilters(filters);
        } catch (SQLException e) {
            logger.error("druid configuration Exception", e);
        }
        datasource.setConnectionProperties(connectionProperties);

        return datasource;
    }
}

然后创建DruidFilter，代码如下：

package com.dalaoyang.filter;
import javax.servlet.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;

import com.alibaba.druid.support.http.WebStatFilter;
/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.filter
 * @email yangyang@dalaoyang.cn
 * @date 2018/4/12
 */


@WebFilter(filterName="druidWebStatFilter",urlPatterns="/*",
        initParams={
                @WebInitParam(name="exclusions",value="*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/druid/*")//忽略资源
        }
)
public class DruidFilter extends WebStatFilter  {
}

新建DruidServlet，在类上面加注解@WebServlet，其中配置了登录druid监控页面的账号密码，白名单黑名单之类的配置，代码如下：

package com.dalaoyang.servlet;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;

import com.alibaba.druid.support.http.StatViewServlet;
/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.servlet
 * @email yangyang@dalaoyang.cn
 * @date 2018/4/12
 */


@WebServlet(urlPatterns="/druid/*",
        initParams={
                @WebInitParam(name="allow",value=""),// IP白名单(没有配置或者为空，则允许所有访问)
                @WebInitParam(name="deny",value=""),// IP黑名单 (deny优先于allow)
                @WebInitParam(name="loginUsername",value="admin"),// 登录druid管理页面用户名
                @WebInitParam(name="loginPassword",value="admin")// 登录druid管理页面密码
        })
public class DruidServlet extends StatViewServlet {

}

然后在启动类加入注解@ServletComponentScan，让项目扫描到servlet，代码如下：

package com.dalaoyang;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;


@SpringBootApplication
// 启动类必须加入@ServletComponentScan注解，否则无法扫描到servlet
@ServletComponentScan
public class SpringbootDruidApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootDruidApplication.class, args);
    }
}

剩余的就是和整合jpa一样的entity（实体类），repository（数据操作层），controller（测试使用的controller），直接展示代码。

City

package com.dalaoyang.entity;

import javax.persistence.*;

/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.Entity
 * @email 397600342@qq.com
 * @date 2018/4/7
 */
@Entity
@Table(name="city")
public class City {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int cityId;
    private String cityName;
    private String cityIntroduce;

    public City(int cityId, String cityName, String cityIntroduce) {
        this.cityId = cityId;
        this.cityName = cityName;
        this.cityIntroduce = cityIntroduce;
    }

    public City(String cityName, String cityIntroduce) {
        this.cityName = cityName;
        this.cityIntroduce = cityIntroduce;
    }

    public City() {
    }

    public int getCityId() {
        return cityId;
    }

    public void setCityId(int cityId) {
        this.cityId = cityId;
    }

    public String getCityName() {
        return cityName;
    }

    public void setCityName(String cityName) {
        this.cityName = cityName;
    }

    public String getCityIntroduce() {
        return cityIntroduce;
    }

    public void setCityIntroduce(String cityIntroduce) {
        this.cityIntroduce = cityIntroduce;
    }
}

CityRepository

package com.dalaoyang.repository;

import com.dalaoyang.entity.City;
import org.springframework.data.jpa.repository.JpaRepository;

/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.Repository
 * @email 397600342@qq.com
 * @date 2018/4/7
 */
public interface CityRepository extends JpaRepository<City,Integer> {
}

CityController

package com.dalaoyang.controller;

import com.dalaoyang.entity.City;
import com.dalaoyang.repository.CityRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.controller
 * @email 397600342@qq.com
 * @date 2018/4/7
 */
@RestController
public class CityController {


    @Autowired
    private CityRepository cityRepository;


    //http://localhost:8888/saveCity?cityName=北京&cityIntroduce=中国首都
    @GetMapping(value = "saveCity")
    public String saveCity(String cityName,String cityIntroduce){
        City city = new City(cityName,cityIntroduce);
        cityRepository.save(city);
        return "success";
    }

    //http://localhost:8888/deleteCity?cityId=2
    @GetMapping(value = "deleteCity")
    public String deleteCity(int cityId){
        cityRepository.delete(cityId);
        return "success";
    }

    //http://localhost:8888/updateCity?cityId=3&cityName=沈阳&cityIntroduce=辽宁省省会
    @GetMapping(value = "updateCity")
    public String updateCity(int cityId,String cityName,String cityIntroduce){
        City city = new City(cityId,cityName,cityIntroduce);
        cityRepository.save(city);
        return "success";
    }


    //http://localhost:8888/getCityById?cityId=3
    @GetMapping(value = "getCityById")
    public City getCityById(int cityId){
        City city = cityRepository.findOne(cityId);
        return city;
    }
}

然后启动项目，可以看到控制台已经创建了city表。

然后访问http://localhost:8888/druid，可以看到如下图：

输入账号密码admin，admin，如下图

然后这时我们可以访问http://localhost:8888/saveCity?cityName=北京&cityIntroduce=中国首都

然后点击导航上面的SQL监控，如下图，

从上图可以看到启动项目创建表的sql已经刚刚执行的sql。到这里整合已经完成了。

源码下载：大老杨码云

个人网站：https://dalaoyang.cn